Automatic welding device and welding skill training device

ABSTRACT

A technique for judging a welding quality for acceptance or rejection and displaying the result in diagrams, and an automatic welding device incorporating the technique therein. When an operation result record status judging means judges that past operation records are available, temperature distribution operation result records at joints of works to be welded are displayed by a weld penetration display means ( 23 ) and bead surface shape operation result records are displayed by a bead surface shape display means ( 25 ), whereby time required for operation by a temperature distribution operation means and time required for operation by a bead surface shape operation means ( 24 ) are omitted by an operation time omitting means incorporated in the automatic welding device.

TECHNICAL FIELD

This invention relates to a fully-automatic welding device, providedwith a manipulator and a quality monitoring mechanism used to monitorthe quality of a melted joint, for melting and joining metals togetherby a welding arc, and this invention relates to a welding skill trainingdevice capable of presenting a welding working condition and capable ofdisplaying a welded-joint section operation result and a welded-jointsurface operation result based on the welding working condition.

BACKGROUND ART

Conventionally, a finish-visual-evaluation system for a welded joint canbe classified into three evaluation types, i.e., a pre-weldingevaluation, an in-welding evaluation, and a post-welding evaluation fromthe temporal viewpoint of evaluation execution, and, when evaluated, thein-welding evaluation and the post-welding evaluation in each of which areal object to be welded is used have been employed in most cases.

With regard to the pre-welding evaluation, there is a method disclosedin Japanese Patent Publication No. Hei-7-47209 in which a plurality ofwelding parameters are stored, thereafter other welding parameters aresequentially determined according to a plurality of condition generatingrules, and a welding condition, which is required when welding, isdetermined by repeating this, and a method disclosed in JapaneseUnexamined Patent Publication No. Hei-5-57436 in which only weldingconditions that correspond to predetermined conditions are stored in adatabase, a welding condition that agrees with a predetermined conditionthat has been input is thereafter retrieved from the database, and, ifthe welding condition is not contained in the database, the weldingcondition is inferred by the use of a welding-condition-data-inferringportion constructed by a neural network, and, if welding conditions aresuitable, all welding conditions employed at that time are registered inthe database.

However, the conventional finish-visual-evaluation system for a weldedjoint is at a disadvantage in the fact that the quality of awelded-joint appearance cannot be evaluated at any time since membergeneration occurs in a to-be-welded object because of the in-weldingevaluation or the post-welding evaluation and since a welder who hasconsiderable skills is required in the work schedule. Anotherdisadvantage is the fact that a welding result cannot be represented inthe form of a graphic figure even if a recommended welding condition ispresented in the case of the pre-welding evaluation.

Additionally, in order to acquire arc-welding skills, a method ofoffering the skills from a skilled welder has been employed, andon-the-job training has been conducted in most cases.

However, the conventional method of acquiring arc-welding skills has aproblem in that a recent decline in the number of skilled welders makesit difficult to offer welding skills to beginning welders who intend tonewly master the skills.

DISCLOSURE OF INVENTION

A first object of the present invention is to solve the aforementionedproblems by means of a technique for judging weld quality for acceptanceor rejection by specifying welding conditions and material parametersbefore welding and displaying the result in diagrams and by means of afully-automatic welding device incorporating the technique thereinto.

A second object of the present invention is to solve the aforementionedproblems by means of a welding skill training device by which abeginning welder can confirm the predicted cross-sectional shape of awelded joint that depends on a welding condition any number of times andfor which a technique for realizing training equal to an offer of skillsfrom a skilled welder is incorporated.

In order to achieve the first object, the automatic welding device ofthe present invention has an optimal welding condition operation meansfor setting information regarding a to-be-welded object that includesboard thickness, outer dimensions, and the joint shape of theto-be-welded object and performing arithmetical operations for weldingconditions that include welding current, welding voltage, and weldingspeed suitable for information, whereby the present invention ischaracterized in that the automatic welding device includes atemperature distribution operation means for performing arithmeticaloperations for a temperature distribution in a joint of the to-be-weldedobject from the information regarding the to-be-welded object and fromthe welding conditions; a temperature distribution operation resultrecording means for recording at least information regarding theto-be-welded object, the welding conditions, and a temperaturedistribution operation result calculated by the temperature distributionoperation means; a weld penetration display means for displaying atleast a penetration width, a penetration depth, and a penetration shapebased on the temperature distribution operation result; a bead surfaceshape operation means for performing arithmetical operations for amolten-metal bead surface shape from at least information regarding theto-be-welded object recorded in the temperature distribution operationresult recording means, the welding conditions, and the temperaturedistribution operation result; a bead surface shape operation resultrecording means for recording a molten-metal bead surface shapeoperation result calculated by the bead surface shape operation means; abead surface shape operation result display means for displaying thesurface shape operation result calculated by the bead surface shapeoperation means by at least a cross-sectional view, a longitudinalsectional view, and a general view of the welded joint; a bead shapeobservation position setting means capable of setting a bead shapeobservation position by a viewing point from an arbitrary position indisplaying the bead surface shape; an arbitrary position bead shapedisplay means for displaying at least the general view of the weldedjoint from a position set by the bead shape observation position settingmeans; a joint quality acceptance/rejection judging means for judgingacceptance or rejection of a joint quality of the to-be-welded objectfrom a temperature distribution in the joint of the to-be-welded objectin the temperature distribution operation result recording means; a weldstarting means for automatically starting to weld the to-be-weldedobject under the welding conditions recorded in the temperaturedistribution operation result recording means when judgment of theacceptance of the joint quality is made in the joint qualityacceptance/rejection judging means; a welding condition correction meansfor correcting the welding conditions of at least the welding current,the welding voltage, and the welding speed to satisfy acceptancecriteria when judgment of the rejection of the joint quality is made inthe joint quality acceptance/rejection judging means; an operationresult record situation judging means for judging the presence orabsence of similar information regarding the to-be-welded object, asimilar temperature distribution operation result record, and a similarbead surface shape operation result record before setting theinformation regarding the to-be-welded object; and an operation timeomitting means for omitting time required for operation by thetemperature distribution operation means and time required for operationby the bead surface shape operation means by allowing the weldpenetration display means to display a temperature distributionoperation result record in the joint of the to-be-welded object and byallowing the bead surface shape display means to display a bead surfaceshape operation result record when the operation result record situationjudging means judges that there is an arithmetical operation record inthe past.

In order to achieve the second object, the welding skill training deviceof the present invention has a welding condition setting means forsetting information regarding a to-be-welded object that includes boardthickness, outer dimensions, and the joint shape of the to-be-weldedobject and presenting welding conditions that include welding current,welding voltage, welding speed, and torch angle suitable forinformation, whereby the present invention is characterized in that thewelding skill training device includes a temperature distributionoperation means for performing arithmetical operations on a temperaturedistribution in a joint of the to-be-welded object from informationregarding the to-be-welded object and from the welding conditions; abead surface shape operation means for performing arithmeticaloperations on a molten-metal bead surface shape from the informationregarding the to-be-welded object, from the welding conditions, and fromthe temperature distribution operation result; a bead shape displaymeans for displaying a welded-joint bead shape by a cross-sectionalview, a longitudinal sectional view, and a general view from a surfaceshape operation result calculated by the surface shape operation meansand a temperature distribution calculated by the temperaturedistribution operation means; a bead shape observation position settingmeans capable of setting a bead shape observation position by a viewingpoint from an arbitrary position in displaying the bead shape; and awelding-condition changing means for changing at least a penetrationwidth, a penetration depth, and a penetration shape based on thetemperature distribution operation result.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a general schematic drawing of a device that embodies thepresent invention, and

FIG. 2 is a block diagram that shows an information flow in anembodiment of the present invention.

FIG. 3 is a flowchart showing one example of an optimal weldingcondition operation means,

FIG. 4 is a flowchart showing one example of a thermal conductionoperation means,

FIG. 5 is a flowchart showing one example of a weld penetration displaymeans,

FIG. 6 is a flowchart showing one example of a bead surface shapeoperation means, and

FIG. 7 is an explanatory diagram showing coordinate systems used forcalculation in the present invention.

FIG. 8 is a flowchart showing one example of a bead surface shapedisplay means,

FIG. 9 is a flowchart showing one example of a temperature distributionoperation result recording means and a surface shape operation resultrecording means, and

FIG. 10 is a flowchart showing one example of a joint qualityacceptance/rejection judging means.

FIG. 11 is a flowchart showing one example of a weld starting means, and

FIG. 12 is a flowchart showing one example of a welding conditioncorrection means.

FIG. 13 is a block diagram showing an information flow in an embodimentof the present invention,

FIG. 14 is a flowchart showing a processing flow in an embodiment of theinvention, and

FIG. 15 is a flowchart showing one example of an input means ofboard-thickness/joint information.

FIG. 16 is a flowchart showing one example of a welding-conditiondatabase,

FIG. 17 is a flowchart showing one example of a standard-conditionpresentation, and

FIG. 18 is a flowchart showing one example of thermal-conductionoperations.

FIG. 19 is a flowchart showing one example of bead shape operations,

FIG. 20 is a flowchart showing one example of the display of a beadshape operation result,

FIG. 21 is a flowchart showing one example of a display position change,

FIG. 22 is a flowchart showing one example of a condition settingchange,

FIG. 23 is a flowchart showing one example of a display position settingchange, and

FIG. 24 is a flowchart showing one example of a welding conditionsetting change.

FIG. 25 shows one example of a standard-condition presentation,

FIG. 26 shows a situation in one example that represents an arithmeticaldevelopment by a bar graph and represents elapsed time by numericalvalues,

FIG. 27 shows a situation in one example of an operation result,

FIG. 28 shows one example of an input screen of a display settingchange, and

FIG. 29 shows one example of an input screen of a welding conditionchange.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be hereinafter described on the basis ofembodiments shown in the figures.

FIG. 1 is a general schematic drawing of an embodiment of a device forachieving the first object of the present invention. 11 designates arobot controller for controlling a robot mechanism 12 and a welder 13.The robot controller 11 and the robot mechanism 12 are connected to eachother by a cable for driving a motor, a cable for feeding backrotational information to the robot controller 11 by an encoder attachedto the motor, etc. A 6-axis vertical articulated type manipulator isused in the robot mechanism 12. 13 designates a teaching pendant forteaching tasks to a robot and displaying various states, which can makea large-screen and multicolor display. 14 designates a welding torch,which has a hole through which a welding wire supplied from a weldingwire container 110 by a wire feeder 19 smoothly passes and a passage fora shielding gas supplied from a shielding-gas cylinder 18 in its inside,and from the tip of which a shielding gas is emitted. A copper-madeelectric supply chip for supplying welding electric power from a weldingsource 17 to the welding wire is attached to the tip of the weldingtorch 14. 15 designates an object work, which is fixed by an object-workfixture 16 and the posture of which is changed thereby.

FIG. 2 is a block diagram that shows an information flow in thisembodiment. 21 designates an optimal welding condition operation means,which displays or inputs information and welding conditions through theteaching pendant 13 of FIG. 1.

22 designates a thermal conduction operation means, which outputs atemperature distribution operation result based on the information andthe welding conditions of a to-be-welded object that have been inputfrom the teaching pendant 13.

23 designates a weld penetration display means, which displays apenetration shape based on a temperature distribution operation resultthat has been output from the thermal conduction operation means 22.

24 designates a bead shape operation means, which outputs a bead shapeoperation result based on a temperature distribution operation resultthat has been output from the thermal conduction operation means 22.

25 designates a bead shape display means, which displays a bead surfaceshape operation result based on a bead surface shape operation resultthat has been output from the bead shape operation means 24 and based ona bead surface shape observation position that has been input from theteaching pendant 13.

26 designates a temperature distribution operation result recordingmeans and a surface shape operation result recording means, whichrecords a temperature distribution operation result that has been outputfrom the thermal conduction operation means 22 and a bead surface shapeoperation result that has been output from the bead shape operationmeans 24.

27 designates a joint quality acceptance/rejection judging means, whichinputs the temperature distribution operation result recording means 26and outputs a joint quality acceptance/rejection judgment result.

28 designates a weld starting means, which starts to weld the objectwork 15 to be welded through the robot mechanism 12 under weldingconditions recorded in the temperature distribution operation resultrecording means 26.

29 designates a welding condition correction means, which inputsconditions that have been obtained by correcting the welding conditionsrecorded in the temperature distribution operation result recordingmeans 26 and in the joint quality acceptance/rejection judging means 27into the optimal welding condition operation means 21.

FIG. 3 is a flowchart showing one example of the optimal weldingcondition operation means, which corresponds to the information flow ofthe optimal welding condition operation means 21, the thermal conductionoperation means 22, the weld penetration display means 23, the beadshape display means 25, and the welding condition correction means 29 ofFIG. 2. One example of optimum welding condition arithmetical operationswill be described with reference to FIG. 3.

Step 31 A worker is required to select or input the board thickness ofthe to-be-welded object from the optimal welding condition operationmeans 21 and to set it.

Step 32 The worker is required to select or input the outer dimensionsof the to-be-welded object from the optimal welding condition operationmeans 21 and to set it.

Step 33 The worker is required to select or input the joint shape of theto-be-welded object from the optimal welding condition operation means21 and to set it.

Step 34 The optimal welding condition operation means 21 is caused todisplay acceptable welding conditions from information that has been setin Steps 31 to 33 and operation result information that has beenrecorded in the recording means 26.

Step 35 The worker is required to manually select or input a weldingcondition from the optimal welding condition operation means 21 and toset it when conditions excluding the welding conditions presented inStep 34 are employed.

Step 36 The worker is required to select or input the viewing point of abead shape observation position in the bead shape display means 26 andto set it.

FIG. 4 is a flowchart showing one example of the thermal conductionoperation means 22, which corresponds to the information flow of thedisplay 23 of the thermal-conduction operation result and the bead shapeoperations 24 of FIG. 2. One example of the thermal-conductionoperations will be described with reference to FIG. 4.

Step 41 The board thickness of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 42 The outer dimensions of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 43 The joint shape of the to-be-welded object set by the optimalwelding condition operation means 21 is input.

Step 44 The welding condition of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 45 Operations are performed according to Differential Equation 1based on parameters that have been input in Steps 41 to 44.$\begin{matrix}{{k\left( {\frac{\partial^{2}T}{\partial\xi^{2}} + \frac{\partial^{2}T}{\partial y^{2}} + \frac{\partial^{2}T}{\partial z^{2}}} \right)} = {{- v}\frac{\partial T}{\partial\xi}}} & {{Equation}\quad 1}\end{matrix}$

wherein k is thermal diffusivity (or temperature diffusivity) [m²/s], Tis temperature [k], and v is the traverse speed of a heat source [m/S].

The coordinate system used for the arithmetical operations is shown inFIG. 7. ?, Y, and Z are coordinate axes perpendicular to one another,and a torch serving as a heat source moves on the ? axis.

Step 46 A temperature distribution operation result of the joint of theto-be-welded object is output, the output result is then displayed bythe weld penetration display means 23, is then used by the bead shapeoperation means 24, and is recorded by the temperature distributionoperation result recording means and the surface shape operation resultrecording means 26.

FIG. 5 is a flowchart showing one example of the weld penetrationdisplay means 23, and corresponding to the information flow of thethermal conduction operation means 22, the temperature distributionoperation result recording means, and the surface shape operation resultrecording means 26.

Step 51 The board thickness of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 52 The outer dimensions of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 53 The joint shape of the to-be-welded object set by the optimalwelding condition operation means 21 is input.

Step 54 The joint temperature distribution operation result of theto-be-welded object calculated by the thermal conduction operation means22 is input.

Step 55 If an operation example exists in the past, the jointtemperature distribution operation result of the to-be-welded objectthat is under the same condition and that has been recorded in thetemperature distribution operation result recording means and in thesurface shape operation result recording means 26 is input.

Step 56 A cross-section temperature distribution display is made basedon the joint temperature distribution operation result of theto-be-welded object calculated by the thermal conduction operation means22 or based on the joint temperature distribution operation result ofthe to-be-welded object that is under the same condition and that hasbeen recorded in the operation result recording means 26.

Step 57 A longitudinal-section temperature distribution display is madebased on the joint temperature distribution operation result of theto-be-welded object calculated by the thermal conduction operation means22 or based on the joint temperature distribution operation result ofthe to-be-welded object that is under the same condition and that hasbeen recorded in the operation result recording means 26.

FIG. 6 is a flowchart showing one example of the bead surface shapeoperation means 24 and corresponding to the information flow of thethermal-conduction operation result display 23 and the bead surfaceshape display 25 of FIG. 2. One example of thermal-conduction operationswill be described with reference to FIG. 6.

Step 61 The board thickness of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 62 The outer dimensions of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 63 The joint shape of the to-be-welded object set by the optimalwelding condition operation means 21 is input.

Step 64 The welding condition of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 65 The temperature distribution operation result of the joint ofthe to-be-welded object calculated by the thermal conduction operationmeans 22 is input.

Step 66 Operations are performed according to Differential Equation 2based on parameters that have been input in Steps 61 to 65.$\begin{matrix}\begin{matrix}{{\sigma \left\{ \frac{{\left( {1 + \varphi_{Y}^{2}} \right)\varphi_{XX}} - {2\varphi_{X}\varphi_{Y}\varphi_{XY}} + {\left( {1 + \varphi_{X}^{2}} \right)\varphi_{YY}}}{\left( {1 + \varphi_{X}^{2} + \varphi_{Y}^{2}} \right)^{\frac{3}{2}}} \right\}} = {{\rho \quad g\quad \varphi} - P_{a} - \lambda}} \\\begin{matrix}{{\varphi_{XX} = \frac{\partial^{2}\varphi}{\partial X^{2}}},} & {{\varphi_{YY} = \frac{\partial^{2}\varphi}{\partial Y^{2}}},} & {\varphi_{XY} = \frac{\partial^{2}\varphi}{{\partial X}{\partial Y}}} \\{{\varphi_{X} = \frac{\partial\varphi}{\partial X}},} & {\varphi_{Y} = \frac{\partial\varphi}{\partial Y}} & \quad\end{matrix}\end{matrix} & {{Equation}\quad 2}\end{matrix}$

wherein

φ_(xx), φ_(XY), φ_(yy): Second-order differential term regarding amolten weld pool surface

φ_(X), φ_(Y): First-order differential term regarding a molten weld poolsurface

In Equation 2, each term is as follows:

φ: Displacement of molten weld pool surface [m]

s: Surface tension (soft steel 0.1428 [kg/m]=1.4 [N/m])

?: Density (soft steel 7.8*103 [kg/m 3])

g: Gravity (9.8 [m/sec z])

Pa: Arc pressure [Pa]

?: Lagrange's multiplier (dimensionless number)

Step 67 The bead surface shape operation result of the joint of theto-be-welded object is output, and this result is displayed by the weldpenetration display means 25, and is recorded by the temperaturedistribution operation result recording means and the surface shapeoperation result recording means 26.

FIG. 8 is a flowchart showing one example of the bead surface shapedisplay means 25 and corresponding to the information flow of theoptimal welding condition operation means 21 and the bead surface shapeoperations 24 of FIG. 2. One example of thermal conduction operationswill be described with reference to FIG. 8.

Step 71 The board thickness of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 72 The outer dimensions of the to-be-welded object set by theoptimal welding condition operation means 21 is input.

Step 73 The joint shape of the to-be-welded object set by the optimalwelding condition operation means 21 is input.

Step 74 The temperature distribution result of the joint of theto-be-welded object calculated by the bead shape operation means 24 isinput.

Step 75 If an example of the bead shape operations exists in the past,the temperature distribution result of the joint of the to-be-weldedobject that is under the same condition and that has been recorded inthe temperature distribution operation result recording means and in thesurface shape operation result recording means 26 is input.

Step 76 The bead shape observation position set by the teaching pendant13 which is the optimal welding condition operation means 21 is input.

Step 77 The bead surface shape is displayed at the bead shapeobservation position.

FIG. 9 is a flowchart showing one example of the temperaturedistribution operation result recording means and the surface shapeoperation result recording means 26 and corresponding to the informationflow of the optimal welding condition operation means 21, the thermalconduction operation means 22, the weld penetration display means 23,the bead surface shape operation means 24, the bead surface shapedisplay means 25, the joint quality acceptance/rejection judging means27, and the welding condition correction means 29 of FIG. 2. One exampleof the temperature distribution operation result recording means and thesurface shape operation result recording means 26 will be described withreference to FIG. 9.

Step 81 Information regarding the to-be-welded object that has beenoutput from the optimal welding condition operation means 21 is inputinto the temperature distribution operation result recording means andthe surface shape operation result recording means 26.

Step 82 A welding condition of the to-be-welded object that has beenoutput from the optimal welding condition operation means 21corresponding to Step 81 is input into the temperature distributionoperation result recording means and the surface shape operation resultrecording means 26.

Step 83 A temperature distribution operation result corresponding toSteps 81 and 82 is input into the temperature distribution operationresult recording means and the surface shape operation result recordingmeans 26.

Step 84 A bead surface shape operation result corresponding to Steps 81,82, and 83 is input into the temperature distribution operation resultrecording means and the surface shape operation result recording means26.

Step 85 Treating the to-be-welded object information of Step 81, theto-be-welded object welding condition of Step 82, the temperaturedistribution operation result of Step 83, and the bead surface shapeoperation result of Step 84 as a group of data, the data is recorded andmanaged by parameters of the to-be-welded object information and theto-be-welded object welding condition in the temperature distributionoperation result recording means and the surface shape operation resultrecording means 26.

FIG. 10 is a flowchart showing one example of the joint qualityacceptance/rejection judging means 27, and corresponding to aninformation flow with the welding condition correction means 29 of FIG.2. One example of the joint quality acceptance/rejection judging means27 will be described with reference to FIG. 10.

Step 91 The temperature distribution operation result and the beadsurface shape operation result that have been recorded in thetemperature distribution operation result recording means and thesurface shape operation result recording means 26 in Step 85 are input.

Step 92 A judgment regarding the weld penetration of the joint is madeaccording to the depth of a penetration part by the temperaturedistribution operation result, and, if the weld penetration issatisfactory, the stage proceeds to Step 93, and, if the weldpenetration is unsatisfactory, the stage proceeds to Step 96.

Step 93 A penetration acceptance flag 00 is generated.

Step 94 According to the bead surface shape operation result, a judgmentis made about the defective phenomena of penetration shortage,incomplete fusion, throat-depth shortage, undercut, overlap, excessmetal shortage, and excess metal surplus. If it is judged that thesephenomena have not occurred, the stage proceeds to Step 94. If it isjudged that one or more of the phenomena have occurred, the stageproceeds to Step 96.

Step 95 A joint quality acceptance flag 0 is generated.

Step 96 An incomplete penetration flag 1 is generated.

Step 97 An incomplete bead shape flag 2 is generated.

FIG. 11 is a flowchart showing one example of the weld starting means 28and corresponding to an information flow with the welding conditioncorrection means 27 of FIG. 2. One example of the weld starting means 28will be described with reference to FIG. 11.

Step 101 The joint quality acceptance flag 0 generated in Step 95 isinput.

Step 102 The welding condition of the to-be-welded object recorded inStep 82 is set.

Step 103 The welding condition set in Step 102 is set for the welder 17of FIG. 2, and the object work 15 to be welded starts to be welded bythe welding torch 14 through the robot mechanism 12.

FIG. 12 corresponds to the information flow of the temperaturedistribution operation result recording means and the surface shapeoperation result recording means 26 and the joint qualityacceptance/rejection judging means 27 of FIG. 2. One example of the weldstarting means 29 will be described with reference to FIG. 12.

Step 111 The penetration acceptance flag 00 generated in Step 93 isinput.

Step 112 The joint quality acceptance flag 0 generated in Step 95 isinput.

Step 113 Board thickness, outer dimensions, and the joint shape of theto-be-welded object which are each information regarding theto-be-welded object are inquired of the temperature distributionoperation result recording means and the surface shape operation resultrecording means 26 of FIG. 2, thereafter welding conditions that havebeen changed are received, and they are given to Step 115.

Step 114 Welding conditions that agree with board thickness, outerdimensions, and the joint shape of the to-be-welded object, which areeach piece of information regarding the to-be-welded object and whichhave been inquired in Step 113, are retrieved in the temperaturedistribution operation result recording means and the surface shapeoperation result recording means 26, and welding conditions that havebeen retrieved are given to Step 113.

Step 115 The welding conditions given from Step 113 are given to theoptimal welding condition operation means 21 of FIG. 2.

Thus, the quality of the joint of the to-be-welded object can be judgedbefore welding without welding expertise.

Next, an embodiment for achieving the second object of the presentinvention will be described with reference to the figures.

FIG. 13 is a block diagram showing an information flow of thisembodiment. 101 designates a welding condition setting means forinputting or displaying information regarding the to-be-welded objectand welding conditions.

102 designates a temperature distribution operation means for outputtinga temperature distribution operation result based on informationregarding the to-be-welded object and welding conditions that have beeninput from the welding condition setting means 101.

103 designates a bead shape operation means for outputting a bead shapeoperation result based on a temperature distribution operation resultthat has been output from the temperature distribution operation means102.

104 designates a bead shape display means for displaying a bead shapebased on a temperature distribution operation result output from thetemperature distribution operation means 102 and based on a bead shapeoperation result output from the bead shape operation means 103.

105 designates a bead shape observation position setting means forchanging/inputting a predetermined condition concerning the observingpoint of a bead shape displayed by the bead shape display means 104.

106 designates a welding-condition changing means for changinginformation regarding the to-be-welded object and welding conditionsthat have been set by the welding condition setting means 101.

FIG. 14 is a flowchart showing this embodiment, and the input 201 ofboard-thickness information and joint information, a welding-conditiondatabase 202, and a standard-condition presentation 203 correspond tothe information flow of the welding condition setting means 101 of FIG.13.

201 designates board thickness information and joint information thatare input by the welding condition setting means.

202 designates a welding-condition database that presents a standardwelding condition in accordance with a board thickness and a joint shapebased on the board thickness information and the joint information ofthe to-be-welded object that has been input by 201.

The standard-condition presentation 203 is a welding condition presentedby the welding-condition database 202.

A thermal conduction operation means 204 corresponds to the informationflow of the temperature distribution operation means 102 of FIG. 13 andperforms thermal-conduction operations according to the weldingcondition 203 that has been presented.

A bead shape operation means 205 corresponds to the information flow ofthe bead surface shape operation means 103 of FIG. 13 and outputs a beadshape operation result based on a temperature distribution operationresult output from the thermal conduction operation means 204.

A display means 206 of a bead shape operation result corresponds to theinformation flow of the bead shape display means 104 of FIG. 13 andoutputs penetration into a base material and a bead surface to anoperation-result display based on operation results of the thermalconduction operation means 204 and the bead shape operation means 205.

A judgment 207 regarding a display position change and a displayposition setting change means 209 correspond to the information flow ofthe bead shape observation position setting means 105 of FIG. 13.

The display position setting change means 209 performsenlargement/reduction, up/down/left/right/front/back, and rotationalchange of the display position of an operation result in real time.

The judgment 207 regarding a display position change and the displayposition setting change 209 correspond to the information flow of thewelding-condition changing means 106 of FIG. 13.

208 designates a judgment regarding a welding condition setting change.

210 designates a welding-condition changing means for changing weldingcurrent, welding voltage, welding speed, and torch angle which arewelding conditions and for again performing arithmetical operations bythe bead shape operation means 205.

FIG. 15 is a flowchart showing one example of the setting ofboard-thickness information and joint information that are input by thewelding condition setting means and corresponding to the informationflow of the input 201 of the board-thickness information and the jointinformation of FIG. 14.

Step 31 An operator is required to select or input the board thicknessof the to-be-welded object from the welding condition setting means andto set it.

Step 32 The operator is required to select or input the outer dimensionsof the to-be-welded object from the welding condition setting means andto set it.

Step 33 The operator is required to select or input the joint shape ofthe to-be-welded object from the welding condition setting means and toset it.

FIG. 16 is a flowchart showing one example of the welding-conditiondatabase 202 and corresponding to the information flow of thewelding-condition database 202 of FIG. 14.

Step 41 The board thickness of the to-be-welded object set by the input201 of the board thickness information and the joint information of FIG.14 is input.

Step 42 The outer dimensions of the to-be-welded object set by the input201 of the board thickness information and the joint information of FIG.14 is input.

Step 43 The joint shape of the to-be-welded object set by the input 201of the board thickness information and the joint information of FIG. 14is input.

Step 44 Based on the board thickness of the to-be-welded object set inStep 41, the outer dimensions of the to-be-welded object set in Step 42,and the joint shape of the to-be-welded object set in Step 43, thewelding current, the welding voltage, and the welding speed which arestandard welding conditions concerning the to-be-welded object stored inthe database are calculated. FIG. 25 shows a standard-conditionpresenting screen 1301.

FIG. 17 is a flowchart showing one example of the presentation 203 ofstandard conditions and corresponding to the information flow of thestandard-condition presentation 203 of FIG. 14. One example of thestandard-condition presentation will be described.

Step 51 Welding current, welding voltage, and welding speed which arestandard conditions calculated in Step 44 are presented.

FIG. 18 is a flowchart showing one example of the thermal-conductionoperations 204 and corresponding to the information flow of thestandard-condition presentation 204 of FIG. 14. One example of thethermal-conduction operations will be described.

Step 61 Based on parameters that have been calculated and input in Step54, iterative operations are performed according to DifferentialEquation 1 mentioned above.

Step 62 A temperature distribution operation result of the to-be-weldedobject is output, and the output result is used by the bead shapeoperation means 205 and is displayed by the display 206 of the beadshape operation result.

FIG. 26 shows one example of a development/time display screen 1401 inwhich an arithmetical development is represented by a bar graph andelapsed time is represented by numerical values.

FIG. 19 is a flowchart showing one example of the bead shape operations205. This corresponds to the information flow of the bead shapeoperations 205 of FIG. 14.

Step 71 The temperature distribution of the joint of the to-be-weldedobject is set based on temperature data calculated in Step 52 of thethermal conduction operation means 204.

Step 72 Based on the parameters input in Step 61, the bead surface shapeoperations are performed according to Differential Equation 2 mentionedabove.

Step 73 A bead surface shape operation result of the joint of theto-be-welded object is output.

FIG. 20 is a flowchart showing one example of the display 206 of thebead shape operation result and corresponding to the information flow ofthe display 206 of the bead shape operation result of FIG. 14.

Step 81 A bead surface shape, a display position which is apredetermined display value of a penetration part, a display angle, anda display magnification are input.

Step 82 A fusion part in a base material of the to-be-welded object thathas been set by the indexing of the penetration part of the basematerial thereof is set and input.

Step 83 Bead surface shape data calculated by the bead shape operations205 is input.

Step 84 The shape operation result is displayed in the form of alongitudinal sectional view, a cross-sectional view, and a surfacebird's-eye view. FIG. 27 shows one example of a display screen 1501 ofthe shape operation result.

FIG. 21 is a flowchart showing one example of the display positionchange 207 and corresponding to the information flow of the displayposition 207 of FIG. 14.

Step 91 The operator judges a change in the display setting of the shapeoperation result of Step 84.

Step 92 To the welding condition setting change of Step 101.

Step 93 To the display setting change 209 of FIG. 14.

FIG. 22 is a flowchart showing one example of the condition settingchange 208 and corresponding to the information flow of the displayposition 208 of FIG. 14.

Step 101 The operator judges a change in the welding condition of theshape operation result of Step 84.

Step 102 To the welding condition change 210 of FIG. 14.

FIG. 23 is a flowchart showing one example of the display setting change209 and corresponding to the information flow of the display position209 of FIG. 14.

Step 111 A bead surface shape and a display position which is a displaysetting value of a penetration part are input.

Step 112 A bead surface shape and a display angle which is a displaysetting value of a penetration part are input.

Step 113 A bead surface shape and a display magnification which is adisplay setting value of a penetration part are input.

Step 114 The display setting conditions that have been input in Steps111 to 113 are transmitted to the display 116 of the bead shapeoperation result of FIG. 14. FIG. 28 shows one example of an inputscreen 1601 of the display setting change.

FIG. 24 is a flowchart showing one example of the welding conditionsetting change 210 and corresponding to the information flow of thedisplay position 210 of FIG. 14.

Step 121 A torch angle, which is a welding condition setting value, isinput.

Step 122 A welding speed, which is a welding condition setting value, isinput.

Step 123 A welding current, which is a welding condition setting value,is input.

Step 124 A welding voltage, which is a welding condition setting value,is input.

Step 125 The welding conditions input in Steps 121 to 124 aretransmitted to the thermal-conduction operations 204 of FIG. 14. FIG. 29shows one example of an input screen 1701 of the welding conditionchange.

As described above, according to the first solution means of the presentinvention, the quality of the joint of the to-be-welded object can bejudged before welding without welding expertise. Additionally, thequality of the joint can be confirmed at any time, and the actual objectof the to-be-welded object becomes unnecessary, and therefore man-hoursspent in quality verification can be reduced, and the cost of samplematerials for quality verification can be reduced.

According to the second means of the present invention, a standardwelding condition and a predicted cross-sectional shape of the weldedjoint are presented by specifying the board thickness and joint shape ofthe to-be-welded object without welding expertise, and a beginningwelder newly changes a torch angle condition and the like, and, as aresult, the worker can confirm the predicted cross-sectional shape of awelded joint that depends on welding conditions any number of times, andtraining equal to an offer of skills from a skilled welder can berealized by the welding skill training device.

INDUSTRIAL APPLICABILITY

The present invention is useful as a fully-automatic welding device anda welding skill training device.

What is claimed is:
 1. An automatic welding device having an optimalwelding condition operation means for setting information regarding ato-be-welded object that includes board thickness, outer dimensions, andjoint shape of the to-be-welded object and for performing arithmeticaloperations on welding conditions that include welding current, weldingvoltage, and welding speed suitable for the information, comprising:temperature distribution operation means for performing arithmeticaloperations on a temperature distribution in a joint of the to-be-weldedobject from the information regarding the to-be-welded object and fromthe welding conditions; temperature distribution operation resultrecording means for recording at least the information regarding theto-be-welded object, the welding conditions, and a temperaturedistribution operation result calculated by the temperature distributionoperation means; weld penetration display means for displaying at leasta penetration width, a penetration depth, and a penetration shape basedon the temperature distribution operation result; bead surface shapeoperation means for performing arithmetical operations on a molten-metalbead surface shape from at least the information regarding theto-be-welded object, the welding conditions, and the temperaturedistribution operation result that have been recorded in the temperaturedistribution operation result recording means; bead surface shapeoperation result recording means for recording a molten-metal beadsurface shape operation result calculated by the bead surface shapeoperation means; bead surface shape operation result display means fordisplaying the surface shape operation result calculated by the beadsurface shape operation means in the form of at least a cross-sectionalview, a longitudinal sectional view, and a general view of a weldedjoint; bead shape observation position setting means capable of settinga bead shape observation position by a viewing point from an arbitraryposition in displaying the bead surface shape; arbitrary position beadshape display means for displaying at least the general view of thewelded joint from a position set by the bead shape observation positionsetting means; joint quality acceptance/rejection judging means forjudging acceptance or rejection of a joint quality of the to-be-weldedobject from a temperature distribution in the joint of the to-be-weldedobject in the temperature distribution operation result recording means;weld starting means for automatically starting to weld the to-be-weldedobject under the welding conditions recorded in the temperaturedistribution operation result recording means when the joint qualityacceptance/rejection judging means judges the joint quality to beacceptable; welding condition correction means for correcting thewelding conditions of at least the welding current, the welding voltage,and the welding speed so as to satisfy acceptance criteria when thejoint quality acceptance/rejection judging means judges the jointquality to be rejectable; operation result record situation judgingmeans for judging the presence or absence of similar informationregarding the to-be-welded object, a similar temperature distributionoperation result record, and a similar bead surface shape operationresult record before setting information regarding the to-be-weldedobject; and operation time omitting means for omitting time required foroperation by the temperature distribution operation means and timerequired for operation by the bead surface shape operation means byallowing the weld penetration display means to display a temperaturedistribution operation result record in the joint of the to-be-weldedobject and by allowing the bead surface shape display means to display abead surface shape operation result record when the operation resultrecord situation judging means judges that there is an arithmeticaloperation record in the past.
 2. The automatic welding device accordingto claim 1 wherein the temperature distribution operation means sets theinformation regarding the to-be-welded object that includes boardthickness, outer dimensions, and joint shape of the to-be-welded objectby the optimal welding condition operation means, and, based on weldingconditions suitable for information regarding the to-be-welded object, atemperature distribution in the joint of the to-be-welded object and ona surface thereof is calculated according to a differentiated formula ofa heat-conduction equation.
 3. The automatic welding device according toclaim 2 wherein the temperature distribution operation result recordingmeans records the welding conditions suitable for information regardingthe to-be-welded object by use of one or more recorders of at least amagnetic medium device, a photo-magnetic medium device, and anelectronic medium device.
 4. The automatic welding device according toclaim 2 wherein the weld penetration display means displays a moredetailed temperature distribution than the temperature distribution ofthe to-be-welded object is displayed, by information regarding theto-be-welded object that has been set by the optimum welding conditioninput device, and by a physical constant of the to-be-welded object thathas been set by the optimum welding condition input devise while payingattention to the penetration width and penetration shape.
 5. Theautomatic welding device according to claim 2 wherein the bead surfaceshape operation means calculates a molten-metal bead surface shape, byinformation regarding the to-be-welded object that has been set by theoptimum welding condition input device, and by a physical constant ofthe to-be-welded object that has been set by the optimum weldingcondition input device according to a curved surface equation and anoptimization method.
 6. The automatic welding device according to claim5 characterized in that the optimization method in the bead surfaceshape operation means is to solve the curved surface equation accordingto one or more of a golden section method which is a one-variable searchmethod, a Fibonacci search method, and a quadratic interpolation methodinside arithmetical operations when a solution is calculated inoperations on the bead surface shape.
 7. The automatic welding deviceaccording to claim 5 wherein the bead surface shape operation resultrecording means records welding conditions suitable for informationregarding the to-be-welded object by the use of one or more recorders ofat least a magnetic medium device, a photo-magnetic medium device, andan electronic medium device.
 8. The automatic welding device accordingto claim 5 wherein the bead surface shape operation result display meansdisplays at least a cross-sectional view, a longitudinal sectional view,and a three-dimensional general view and by information regarding theto-be-welded object set by the optimum welding condition input device.9. The automatic welding device according to claim 8 wherein thearbitrary position bead shape display means enables an operator toobserve the three-dimensional general view from an arbitrary viewingpoint at least by information regarding the to-be-welded object and bythe viewing-point information set by the bead shape observation positionsetting means.
 10. The automatic welding device according to claim 1wherein the bead shape observation position setting means determines aviewing-point setting position for observing the bead surface shapeaccording to viewing-point information that has been set by the optimumwelding condition input device.
 11. The automatic welding deviceaccording to claim 1 wherein the joint quality acceptance/rejectionjudging means judges whether the joint quality of the to-be-weldedobject is acceptable or rejectable by estimating at least one of thephenomena of penetration shortage, imperfect fusion, throat-depthshortage, undercut, overlap, excess metal shortage, and excess metalsurplus at least based on information regarding the to-be-welded objectset by the welding condition input device and based on the bead surfaceshape operation result.
 12. The automatic welding device according toclaim 1 wherein the weld starting means starts welding by use of thewelding conditions of at least the welding current, the welding voltageand the welding speed that have been recorded in the temperaturedistribution calculation result recording means.
 13. The automaticwelding device according to claim 1 wherein the operation result recordsituation judging means retrieves/judges the presence or absence ofsimilar information regarding the to-be-welded object in a record of thetemperature distribution operation result and in a record of the beadsurface shape operation result when information regarding theto-be-welded object is set.
 14. The automatic welding device accordingto claim 1 wherein the welding condition correction means transformsrejected welding conditions into acceptable conditions, and displayscorrected welding conditions by use of data that has been recorded inthe temperature distribution calculation result recording means and byuse of conditions that have been set from the welding condition inputdevice in the joint quality acceptance/rejection judging means.
 15. Theautomatic welding device according to claim 1 wherein a temperaturedistribution in the joint of the to-be-welded object recorded in thetemperature distribution operation result recording means is displayedby the weld penetration display means, and a molten-metal bead surfaceshape recorded in the bead surface shape operation result recordingmeans is displayed by the bead surface shape operation result displaymeans, and thereby the operation time omitting means omits eacharithmetical operation and shortens/omits time needed until a displayimage appears if there is an example that agrees with informationregarding the to-be-welded object and the welding conditions in thetemperature distribution operation result recording means and in thebead surface shape operation result recording means when informationregarding the to-be-welded object and the welding conditions are setfrom the welding condition input device.
 16. A welding skill trainingdevice having a welding condition setting means for setting informationregarding a to-be-welded object that includes board thickness, outerdimensions, and joint shape of the to-be-welded object and presentingwelding conditions that include welding current, welding voltage,welding speed, and torch angle suitable for the information, comprising:temperature distribution operation means for performing arithmeticaloperations for a temperature distribution in a joint of the to-be-weldedobject from information regarding the to-be-welded object and from thewelding conditions; bead surface shape operation means for performingarithmetical operations on a molten-metal bead surface shape frominformation regarding the to-be-welded object, from the weldingconditions, and from the temperature distribution operation result; beadshape display means for displaying a welded-joint bead shape by across-sectional view, a longitudinal sectional view, and a general viewfrom a surface shape operation result calculated by the surface shapeoperation means and a temperature distribution calculated by thetemperature distribution operation means; bead shape observationposition setting means capable of setting a bead shape observationposition by a viewing point from an arbitrary position in displaying thebead shape; and welding-condition changing means for changing at least apenetration width, a penetration depth, and a penetration shape based onthe temperature distribution operation result.
 17. The welding skilltraining device according to claim 16 wherein the temperaturedistribution operation means sets information regarding the to-be-weldedobject that includes at least board thickness, outer dimensions, andjoint shape of the to-be-welded object by the welding condition settingmeans, and, based on welding conditions suitable for informationregarding the to-be-welded object, a temperature distribution in thejoint of the to-be-welded object and on a surface thereof is calculatedaccording to a differentiated formula of a heat-conduction equation. 18.The welding skill training device according to claim 17 wherein the beadsurface shape operation means calculates a molten-metal bead surfaceshape at least by an operation result of a temperature distribution, byinformation regarding the to-be-welded object that has been set by thewelding condition setting means, and by a physical constant of theto-be-welded object that has been set by the welding condition settingmeans according to a curved surface equation.
 19. The welding skilltraining device according to claim 18 wherein the bead shape displaymeans displays at least a cross-sectional view, a longitudinal sectionalview, and a three-dimensional general view and by theboard-thickness/joint information regarding the to-be-welded object setby the welding condition setting means.
 20. The welding skill trainingdevice according to claim 17 wherein the welding-condition changingmeans changes at least the torch angle, the welding current, the weldingvoltage, and the welding speed which are welding conditions of theto-be-welded object, and thereby enables an operator to perform are-calculation of the temperature distribution.
 21. The welding skilltraining device according to claim 16 wherein the bead shape observationposition setting means determines a viewing-point setting position forobserving the bead surface shape according to viewing-point informationset by the welding condition setting means.